U.S. Pat. No. 4,864,410, issued Sep. 5, 1989 to Andrews et al., illustrates a technique using a beam splitter, electronic camera, and a video display (CRT) to simultaneously capture and view a subject on the same optical axis similar to the function of a conventional optical mirror. The images captured by the camera can be processed prior to display to provide special effects such as the distortions employed in a fun-house mirror. The problem with this technique is that the displayed image appears to be located at a distance behind the beam splitter, compromising the “mirror-like” function of the unit. In addition, the video display device must be masked off or it may be viewable by the user also detracting from the “mirror experience”. It is well known and desirable to use a touch screen as a means for providing an interface between a user and a display device such as a CRT, however with the arrangement described by Andrews et al., the interface with a touch screen located between the user and the beam splitter does not provide a satisfactory feel, since when the subject places her finger on the touch screen, the image of the subject's finger does not appear to be located at the screen, rather it appears to be displaced to the rear of the screen.
Using a conventional rear projection screen and a digital projector would provide a display image that would appear in a viewing plane like a conventional mirror, and would function in a satisfactory manner with a touch screen interface, but a conventional rear projection screen would prevent the camera from “seeing” the subject, unless a hole was provided in the center of the screen. This is not a very satisfactory solution.
U.S. Pat. No. 5,801,758 issued Sep. 1, 1998 to Heirich discloses a system for image capture and display. The system includes an image capture apparatus, an image projection apparatus, and an optical switching device that switches an optical path between the image capture and the image projection apparatus. A highly transparent surface, such as a sheet of clear glass is used as a display screen through which the image capture apparatus can view a user, and onto which the image of the user is projected. The problem with this arrangement is that the highly transparent surface allows the user to directly view the projection lens of the image projection apparatus. Any image formed on the highly transparent surface is overwhelmed by the bright appearance of the projection lens.
Another problem in the prior art is the ability to capture an image of person on the same optical axis on which the person is viewing a display device. For example, with regard to video conferencing, a capture camera is positioned at an optical axis different from which the person is viewing the other individual on the video conference call. The problem with the described situation is that the person viewing the display while being recorded by an off-axis camera appears to fail to make eye contact with the recording camera and whoever may be viewing that image. There is a similar problem with an individual using a teleprompter. A person reading from a teleprompter is looking in a direction off axis from the optical axis of a camera capturing the image of the reader.
There is a need therefore for an improved image capture and display device that avoids the shortcomings of the prior art.